xref: /netbsd-src/sys/netinet6/nd6_nbr.c (revision 7cc2f76925f078d01ddc9e640a98f4ccfc9f8c3b)
1 /*	$NetBSD: nd6_nbr.c,v 1.23 2000/11/05 17:17:16 onoe Exp $	*/
2 /*	$KAME: nd6_nbr.c,v 1.36 2000/05/17 12:35:59 jinmei Exp $	*/
3 
4 /*
5  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the project nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #include "opt_inet.h"
34 #include "opt_ipsec.h"
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/malloc.h>
39 #include <sys/mbuf.h>
40 #include <sys/socket.h>
41 #include <sys/sockio.h>
42 #include <sys/time.h>
43 #include <sys/kernel.h>
44 #include <sys/errno.h>
45 #include <sys/ioctl.h>
46 #include <sys/syslog.h>
47 #include <sys/queue.h>
48 #include <sys/callout.h>
49 
50 #include <net/if.h>
51 #include <net/if_types.h>
52 #include <net/if_dl.h>
53 #include <net/route.h>
54 
55 #include <netinet/in.h>
56 #include <netinet/in_var.h>
57 #include <netinet6/in6_var.h>
58 #include <netinet/ip6.h>
59 #include <netinet6/ip6_var.h>
60 #include <netinet6/nd6.h>
61 #include <netinet/icmp6.h>
62 
63 #ifdef IPSEC
64 #include <netinet6/ipsec.h>
65 #endif
66 
67 #include <net/net_osdep.h>
68 
69 #define SDL(s) ((struct sockaddr_dl *)s)
70 
71 struct dadq;
72 static struct dadq *nd6_dad_find __P((struct ifaddr *));
73 static void nd6_dad_timer __P((struct ifaddr *));
74 static void nd6_dad_ns_output __P((struct dadq *, struct ifaddr *));
75 static void nd6_dad_ns_input __P((struct ifaddr *));
76 static void nd6_dad_na_input __P((struct ifaddr *));
77 
78 static int dad_ignore_ns = 0;	/* ignore NS in DAD - specwise incorrect*/
79 static int dad_maxtry = 15;	/* max # of *tries* to transmit DAD packet */
80 
81 /*
82  * Input an Neighbor Solicitation Message.
83  *
84  * Based on RFC 2461
85  * Based on RFC 2462 (duplicated address detection)
86  */
87 void
88 nd6_ns_input(m, off, icmp6len)
89 	struct mbuf *m;
90 	int off, icmp6len;
91 {
92 	struct ifnet *ifp = m->m_pkthdr.rcvif;
93 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
94 	struct nd_neighbor_solicit *nd_ns;
95 	struct in6_addr saddr6 = ip6->ip6_src;
96 	struct in6_addr daddr6 = ip6->ip6_dst;
97 	struct in6_addr taddr6;
98 	struct in6_addr myaddr6;
99 	char *lladdr = NULL;
100 	struct ifaddr *ifa;
101 	int lladdrlen = 0;
102 	int anycast = 0, proxy = 0, tentative = 0;
103 	int tlladdr;
104 	union nd_opts ndopts;
105 	struct sockaddr_dl *proxydl = NULL;
106 
107 	if (ip6->ip6_hlim != 255) {
108 		log(LOG_ERR,
109 		    "nd6_ns_input: invalid hlim %d\n", ip6->ip6_hlim);
110 		goto freeit;
111 	}
112 
113 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
114 		/* dst has to be solicited node multicast address. */
115 		if (daddr6.s6_addr16[0] == IPV6_ADDR_INT16_MLL
116 		    /*don't check ifindex portion*/
117 		    && daddr6.s6_addr32[1] == 0
118 		    && daddr6.s6_addr32[2] == IPV6_ADDR_INT32_ONE
119 		    && daddr6.s6_addr8[12] == 0xff) {
120 			; /*good*/
121 		} else {
122 			log(LOG_INFO, "nd6_ns_input: bad DAD packet "
123 				"(wrong ip6 dst)\n");
124 			goto bad;
125 		}
126 	}
127 
128 #ifndef PULLDOWN_TEST
129 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
130 	nd_ns = (struct nd_neighbor_solicit *)((caddr_t)ip6 + off);
131 #else
132 	IP6_EXTHDR_GET(nd_ns, struct nd_neighbor_solicit *, m, off, icmp6len);
133 	if (nd_ns == NULL) {
134 		icmp6stat.icp6s_tooshort++;
135 		return;
136 	}
137 #endif
138 	taddr6 = nd_ns->nd_ns_target;
139 
140 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
141 		log(LOG_INFO, "nd6_ns_input: bad NS target (multicast)\n");
142 		goto bad;
143 	}
144 
145 	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
146 		taddr6.s6_addr16[1] = htons(ifp->if_index);
147 
148 	icmp6len -= sizeof(*nd_ns);
149 	nd6_option_init(nd_ns + 1, icmp6len, &ndopts);
150 	if (nd6_options(&ndopts) < 0) {
151 		log(LOG_INFO, "nd6_ns_input: invalid ND option, ignored\n");
152 		goto bad;
153 	}
154 
155 	if (ndopts.nd_opts_src_lladdr) {
156 		lladdr = (char *)(ndopts.nd_opts_src_lladdr +1);
157 		lladdrlen = ndopts.nd_opts_src_lladdr->nd_opt_len << 3;
158 	}
159 
160 	if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src) && lladdr) {
161 		log(LOG_INFO, "nd6_ns_input: bad DAD packet "
162 			"(link-layer address option)\n");
163 		goto bad;
164 	}
165 
166 	/*
167 	 * Attaching target link-layer address to the NA?
168 	 * (RFC 2461 7.2.4)
169 	 *
170 	 * NS IP dst is unicast/anycast			MUST NOT add
171 	 * NS IP dst is solicited-node multicast	MUST add
172 	 *
173 	 * In implementation, we add target link-layer address by default.
174 	 * We do not add one in MUST NOT cases.
175 	 */
176 #if 0 /* too much! */
177 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &daddr6);
178 	if (ifa && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST))
179 		tlladdr = 0;
180 	else
181 #endif
182 	if (!IN6_IS_ADDR_MULTICAST(&daddr6))
183 		tlladdr = 0;
184 	else
185 		tlladdr = 1;
186 
187 	/*
188 	 * Target address (taddr6) must be either:
189 	 * (1) Valid unicast/anycast address for my receiving interface,
190 	 * (2) Unicast address for which I'm offering proxy service, or
191 	 * (3) "tentative" address on which DAD is being performed.
192 	 */
193 	/* (1) and (3) check. */
194 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
195 
196 	/* (2) check. */
197 	if (!ifa) {
198 		struct rtentry *rt;
199 		struct sockaddr_in6 tsin6;
200 
201 		bzero(&tsin6, sizeof tsin6);
202 		tsin6.sin6_len = sizeof(struct sockaddr_in6);
203 		tsin6.sin6_family = AF_INET6;
204 		tsin6.sin6_addr = taddr6;
205 
206 		rt = rtalloc1((struct sockaddr *)&tsin6, 0);
207 		if (rt && (rt->rt_flags & RTF_ANNOUNCE) != 0 &&
208 		    rt->rt_gateway->sa_family == AF_LINK) {
209 			/*
210 			 * proxy NDP for single entry
211 			 */
212 			ifa = (struct ifaddr *)in6ifa_ifpforlinklocal(ifp,
213 				IN6_IFF_NOTREADY|IN6_IFF_ANYCAST);
214 			if (ifa) {
215 				proxy = 1;
216 				proxydl = SDL(rt->rt_gateway);
217 			}
218 		}
219 		if (rt)
220 			rtfree(rt);
221 	}
222 	if (!ifa) {
223 		/*
224 		 * We've got a NS packet, and we don't have that adddress
225 		 * assigned for us.  We MUST silently ignore it.
226 		 * See RFC2461 7.2.3.
227 		 */
228 		goto freeit;
229 	}
230 	myaddr6 = *IFA_IN6(ifa);
231 	anycast = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_ANYCAST;
232 	tentative = ((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE;
233 	if (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_DUPLICATED)
234 		goto freeit;
235 
236 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
237 		log(LOG_INFO,
238 		    "nd6_ns_input: lladdrlen mismatch for %s "
239 		    "(if %d, NS packet %d)\n",
240 			ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2);
241 	}
242 
243 	if (IN6_ARE_ADDR_EQUAL(&myaddr6, &saddr6)) {
244 		log(LOG_INFO,
245 		    "nd6_ns_input: duplicate IP6 address %s\n",
246 		    ip6_sprintf(&saddr6));
247 		goto freeit;
248 	}
249 
250 	/*
251 	 * We have neighbor solicitation packet, with target address equals to
252 	 * one of my tentative address.
253 	 *
254 	 * src addr	how to process?
255 	 * ---		---
256 	 * multicast	of course, invalid (rejected in ip6_input)
257 	 * unicast	somebody is doing address resolution -> ignore
258 	 * unspec	dup address detection
259 	 *
260 	 * The processing is defined in RFC 2462.
261 	 */
262 	if (tentative) {
263 		/*
264 		 * If source address is unspecified address, it is for
265 		 * duplicated address detection.
266 		 *
267 		 * If not, the packet is for addess resolution;
268 		 * silently ignore it.
269 		 */
270 		if (IN6_IS_ADDR_UNSPECIFIED(&saddr6))
271 			nd6_dad_ns_input(ifa);
272 
273 		goto freeit;
274 	}
275 
276 	/*
277 	 * If the source address is unspecified address, entries must not
278 	 * be created or updated.
279 	 * It looks that sender is performing DAD.  Output NA toward
280 	 * all-node multicast address, to tell the sender that I'm using
281 	 * the address.
282 	 * S bit ("solicited") must be zero.
283 	 */
284 	if (IN6_IS_ADDR_UNSPECIFIED(&saddr6)) {
285 		saddr6 = in6addr_linklocal_allnodes;
286 		saddr6.s6_addr16[1] = htons(ifp->if_index);
287 		nd6_na_output(ifp, &saddr6, &taddr6,
288 			      ((anycast || proxy || !tlladdr)
289 				      ? 0 : ND_NA_FLAG_OVERRIDE)
290 			      	| (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0),
291 			      tlladdr, (struct sockaddr *)proxydl);
292 		goto freeit;
293 	}
294 
295 	nd6_cache_lladdr(ifp, &saddr6, lladdr, lladdrlen, ND_NEIGHBOR_SOLICIT, 0);
296 
297 	nd6_na_output(ifp, &saddr6, &taddr6,
298 		      ((anycast || proxy || !tlladdr) ? 0 : ND_NA_FLAG_OVERRIDE)
299 			| (ip6_forwarding ? ND_NA_FLAG_ROUTER : 0)
300 			| ND_NA_FLAG_SOLICITED,
301 		      tlladdr, (struct sockaddr *)proxydl);
302  freeit:
303 	m_freem(m);
304 	return;
305 
306  bad:
307 	log(LOG_ERR, "nd6_ns_input: src=%s\n", ip6_sprintf(&saddr6));
308 	log(LOG_ERR, "nd6_ns_input: dst=%s\n", ip6_sprintf(&daddr6));
309 	log(LOG_ERR, "nd6_ns_input: tgt=%s\n", ip6_sprintf(&taddr6));
310 	m_freem(m);
311 }
312 
313 /*
314  * Output an Neighbor Solicitation Message. Caller specifies:
315  *	- ICMP6 header source IP6 address
316  *	- ND6 header target IP6 address
317  *	- ND6 header source datalink address
318  *
319  * Based on RFC 2461
320  * Based on RFC 2462 (duplicated address detection)
321  */
322 void
323 nd6_ns_output(ifp, daddr6, taddr6, ln, dad)
324 	struct ifnet *ifp;
325 	struct in6_addr *daddr6, *taddr6;
326 	struct llinfo_nd6 *ln;	/* for source address determination */
327 	int dad;	/* duplicated address detection */
328 {
329 	struct mbuf *m;
330 	struct ip6_hdr *ip6;
331 	struct nd_neighbor_solicit *nd_ns;
332 	struct in6_ifaddr *ia = NULL;
333 	struct ip6_moptions im6o;
334 	int icmp6len;
335 	int maxlen;
336 	caddr_t mac;
337 	struct ifnet *outif = NULL;
338 
339 	if (IN6_IS_ADDR_MULTICAST(taddr6))
340 		return;
341 
342 	/* estimate the size of message */
343 	maxlen = sizeof(*ip6) + sizeof(*nd_ns);
344 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
345 	if (max_linkhdr + maxlen >= MCLBYTES) {
346 #ifdef DIAGNOSTIC
347 		printf("nd6_ns_output: max_linkhdr + maxlen >= MCLBYTES "
348 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
349 #endif
350 		return;
351 	}
352 
353 	MGETHDR(m, M_DONTWAIT, MT_DATA);
354 	if (m && max_linkhdr + maxlen >= MHLEN) {
355 		MCLGET(m, M_DONTWAIT);
356 		if ((m->m_flags & M_EXT) == 0) {
357 			m_free(m);
358 			m = NULL;
359 		}
360 	}
361 	if (m == NULL)
362 		return;
363 
364 	if (daddr6 == NULL || IN6_IS_ADDR_MULTICAST(daddr6)) {
365 		m->m_flags |= M_MCAST;
366 		im6o.im6o_multicast_ifp = ifp;
367 		im6o.im6o_multicast_hlim = 255;
368 		im6o.im6o_multicast_loop = 0;
369 	}
370 
371 	icmp6len = sizeof(*nd_ns);
372 	m->m_pkthdr.len = m->m_len = sizeof(*ip6) + icmp6len;
373 	m->m_data += max_linkhdr;	/*or MH_ALIGN() equivalent?*/
374 
375 	/* fill neighbor solicitation packet */
376 	ip6 = mtod(m, struct ip6_hdr *);
377 	ip6->ip6_flow = 0;
378 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
379 	ip6->ip6_vfc |= IPV6_VERSION;
380 	/* ip6->ip6_plen will be set later */
381 	ip6->ip6_nxt = IPPROTO_ICMPV6;
382 	ip6->ip6_hlim = 255;
383 	if (daddr6)
384 		ip6->ip6_dst = *daddr6;
385 	else {
386 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
387 		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
388 		ip6->ip6_dst.s6_addr32[1] = 0;
389 		ip6->ip6_dst.s6_addr32[2] = IPV6_ADDR_INT32_ONE;
390 		ip6->ip6_dst.s6_addr32[3] = taddr6->s6_addr32[3];
391 		ip6->ip6_dst.s6_addr8[12] = 0xff;
392 	}
393 	if (!dad) {
394 #if 0	/* KAME way, exact address scope match */
395 		/*
396 		 * Select a source whose scope is the same as that of the dest.
397 		 * Typically, the dest is link-local solicitation multicast
398 		 * (i.e. neighbor discovery) or link-local/global unicast
399 		 * (i.e. neighbor un-reachability detection).
400 		 */
401 		ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
402 		if (ia == NULL) {
403 			m_freem(m);
404 			return;
405 		}
406 		ip6->ip6_src = ia->ia_addr.sin6_addr;
407 #else	/* spec-wise correct */
408 		/*
409 		 * RFC2461 7.2.2:
410 		 * "If the source address of the packet prompting the
411 		 * solicitation is the same as one of the addresses assigned
412 		 * to the outgoing interface, that address SHOULD be placed
413 		 * in the IP Source Address of the outgoing solicitation.
414 		 * Otherwise, any one of the addresses assigned to the
415 		 * interface should be used."
416 		 *
417 		 * We use the source address for the prompting packet
418 		 * (saddr6), if:
419 		 * - saddr6 is given from the caller (by giving "ln"), and
420 		 * - saddr6 belongs to the outgoing interface.
421 		 * Otherwise, we perform a scope-wise match.
422 		 */
423 		struct ip6_hdr *hip6;		/*hold ip6*/
424 		struct in6_addr *saddr6;
425 
426 		if (ln && ln->ln_hold) {
427 			hip6 = mtod(ln->ln_hold, struct ip6_hdr *);
428 			/* XXX pullup? */
429 			if (sizeof(*hip6) < ln->ln_hold->m_len)
430 				saddr6 = &hip6->ip6_src;
431 			else
432 				saddr6 = NULL;
433 		} else
434 			saddr6 = NULL;
435 		if (saddr6 && in6ifa_ifpwithaddr(ifp, saddr6))
436 			bcopy(saddr6, &ip6->ip6_src, sizeof(*saddr6));
437 		else {
438 			ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
439 			if (ia == NULL) {
440 				m_freem(m);	/*XXX*/
441 				return;
442 			}
443 			ip6->ip6_src = ia->ia_addr.sin6_addr;
444 		}
445 #endif
446 	} else {
447 		/*
448 		 * Source address for DAD packet must always be IPv6
449 		 * unspecified address. (0::0)
450 		 */
451 		bzero(&ip6->ip6_src, sizeof(ip6->ip6_src));
452 	}
453 	nd_ns = (struct nd_neighbor_solicit *)(ip6 + 1);
454 	nd_ns->nd_ns_type = ND_NEIGHBOR_SOLICIT;
455 	nd_ns->nd_ns_code = 0;
456 	nd_ns->nd_ns_reserved = 0;
457 	nd_ns->nd_ns_target = *taddr6;
458 
459 	if (IN6_IS_SCOPE_LINKLOCAL(&nd_ns->nd_ns_target))
460 		nd_ns->nd_ns_target.s6_addr16[1] = 0;
461 
462 	/*
463 	 * Add source link-layer address option.
464 	 *
465 	 *				spec		implementation
466 	 *				---		---
467 	 * DAD packet			MUST NOT	do not add the option
468 	 * there's no link layer address:
469 	 *				impossible	do not add the option
470 	 * there's link layer address:
471 	 *	Multicast NS		MUST add one	add the option
472 	 *	Unicast NS		SHOULD add one	add the option
473 	 */
474 	if (!dad && (mac = nd6_ifptomac(ifp))) {
475 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
476 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_ns + 1);
477 		/* 8 byte alignments... */
478 		optlen = (optlen + 7) & ~7;
479 
480 		m->m_pkthdr.len += optlen;
481 		m->m_len += optlen;
482 		icmp6len += optlen;
483 		bzero((caddr_t)nd_opt, optlen);
484 		nd_opt->nd_opt_type = ND_OPT_SOURCE_LINKADDR;
485 		nd_opt->nd_opt_len = optlen >> 3;
486 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
487 	}
488 
489 	ip6->ip6_plen = htons((u_short)icmp6len);
490 	nd_ns->nd_ns_cksum = 0;
491 	nd_ns->nd_ns_cksum
492 		= in6_cksum(m, IPPROTO_ICMPV6, sizeof(*ip6), icmp6len);
493 
494 #ifdef IPSEC
495 	/* Don't lookup socket */
496 	ipsec_setsocket(m, NULL);
497 #endif
498 	ip6_output(m, NULL, NULL, dad ? IPV6_DADOUTPUT : 0, &im6o, &outif);
499 	if (outif) {
500 		icmp6_ifstat_inc(outif, ifs6_out_msg);
501 		icmp6_ifstat_inc(outif, ifs6_out_neighborsolicit);
502 	}
503 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_SOLICIT]++;
504 }
505 
506 /*
507  * Neighbor advertisement input handling.
508  *
509  * Based on RFC 2461
510  * Based on RFC 2462 (duplicated address detection)
511  *
512  * the following items are not implemented yet:
513  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
514  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
515  */
516 void
517 nd6_na_input(m, off, icmp6len)
518 	struct mbuf *m;
519 	int off, icmp6len;
520 {
521 	struct ifnet *ifp = m->m_pkthdr.rcvif;
522 	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
523 	struct nd_neighbor_advert *nd_na;
524 #if 0
525 	struct in6_addr saddr6 = ip6->ip6_src;
526 #endif
527 	struct in6_addr daddr6 = ip6->ip6_dst;
528 	struct in6_addr taddr6;
529 	int flags;
530 	int is_router;
531 	int is_solicited;
532 	int is_override;
533 	char *lladdr = NULL;
534 	int lladdrlen = 0;
535 	struct ifaddr *ifa;
536 	struct llinfo_nd6 *ln;
537 	struct rtentry *rt;
538 	struct sockaddr_dl *sdl;
539 	union nd_opts ndopts;
540 
541 	if (ip6->ip6_hlim != 255) {
542 		log(LOG_ERR,
543 		    "nd6_na_input: invalid hlim %d\n", ip6->ip6_hlim);
544 		goto freeit;
545 	}
546 
547 #ifndef PULLDOWN_TEST
548 	IP6_EXTHDR_CHECK(m, off, icmp6len,);
549 	nd_na = (struct nd_neighbor_advert *)((caddr_t)ip6 + off);
550 #else
551 	IP6_EXTHDR_GET(nd_na, struct nd_neighbor_advert *, m, off, icmp6len);
552 	if (nd_na == NULL) {
553 		icmp6stat.icp6s_tooshort++;
554 		return;
555 	}
556 #endif
557 	taddr6 = nd_na->nd_na_target;
558 	flags = nd_na->nd_na_flags_reserved;
559 	is_router = ((flags & ND_NA_FLAG_ROUTER) != 0);
560 	is_solicited = ((flags & ND_NA_FLAG_SOLICITED) != 0);
561 	is_override = ((flags & ND_NA_FLAG_OVERRIDE) != 0);
562 
563 	if (IN6_IS_SCOPE_LINKLOCAL(&taddr6))
564 		taddr6.s6_addr16[1] = htons(ifp->if_index);
565 
566 	if (IN6_IS_ADDR_MULTICAST(&taddr6)) {
567 		log(LOG_ERR,
568 		    "nd6_na_input: invalid target address %s\n",
569 		    ip6_sprintf(&taddr6));
570 		goto freeit;
571 	}
572 	if (IN6_IS_ADDR_MULTICAST(&daddr6))
573 		if (is_solicited) {
574 			log(LOG_ERR,
575 			    "nd6_na_input: a solicited adv is multicasted\n");
576 			goto freeit;
577 		}
578 
579 	icmp6len -= sizeof(*nd_na);
580 	nd6_option_init(nd_na + 1, icmp6len, &ndopts);
581 	if (nd6_options(&ndopts) < 0) {
582 		log(LOG_INFO, "nd6_na_input: invalid ND option, ignored\n");
583 		goto freeit;
584 	}
585 
586 	if (ndopts.nd_opts_tgt_lladdr) {
587 		lladdr = (char *)(ndopts.nd_opts_tgt_lladdr + 1);
588 		lladdrlen = ndopts.nd_opts_tgt_lladdr->nd_opt_len << 3;
589 	}
590 
591 	ifa = (struct ifaddr *)in6ifa_ifpwithaddr(ifp, &taddr6);
592 
593 	/*
594 	 * Target address matches one of my interface address.
595 	 *
596 	 * If my address is tentative, this means that there's somebody
597 	 * already using the same address as mine.  This indicates DAD failure.
598 	 * This is defined in RFC 2462.
599 	 *
600 	 * Otherwise, process as defined in RFC 2461.
601 	 */
602 	if (ifa
603 	 && (((struct in6_ifaddr *)ifa)->ia6_flags & IN6_IFF_TENTATIVE)) {
604 		nd6_dad_na_input(ifa);
605 		goto freeit;
606 	}
607 
608 	/* Just for safety, maybe unnecessery. */
609 	if (ifa) {
610 		log(LOG_ERR,
611 		    "nd6_na_input: duplicate IP6 address %s\n",
612 		    ip6_sprintf(&taddr6));
613 		goto freeit;
614 	}
615 
616 	if (lladdr && ((ifp->if_addrlen + 2 + 7) & ~7) != lladdrlen) {
617 		log(LOG_INFO,
618 		    "nd6_na_input: lladdrlen mismatch for %s "
619 		    "(if %d, NA packet %d)\n",
620 			ip6_sprintf(&taddr6), ifp->if_addrlen, lladdrlen - 2);
621 	}
622 
623 	/*
624 	 * If no neighbor cache entry is found, NA SHOULD silently be discarded.
625 	 */
626 	rt = nd6_lookup(&taddr6, 0, ifp);
627 	if ((rt == NULL) ||
628 	   ((ln = (struct llinfo_nd6 *)rt->rt_llinfo) == NULL) ||
629 	   ((sdl = SDL(rt->rt_gateway)) == NULL))
630 		goto freeit;
631 
632 	if (ln->ln_state == ND6_LLINFO_INCOMPLETE) {
633 		/*
634 		 * If the link-layer has address, and no lladdr option came,
635 		 * discard the packet.
636 		 */
637 		if (ifp->if_addrlen && !lladdr)
638 			goto freeit;
639 
640 		/*
641 		 * Record link-layer address, and update the state.
642 		 */
643 		sdl->sdl_alen = ifp->if_addrlen;
644 		bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
645 		if (is_solicited) {
646 			ln->ln_state = ND6_LLINFO_REACHABLE;
647 			if (ln->ln_expire)
648 				ln->ln_expire = time.tv_sec +
649 					nd_ifinfo[rt->rt_ifp->if_index].reachable;
650 		} else
651 			ln->ln_state = ND6_LLINFO_STALE;
652 		ln->ln_router = is_router;
653 	} else {
654 		int llchange;
655 
656 		/*
657 		 * Check if the link-layer address has changed or not.
658 		 */
659 		if (!lladdr)
660 			llchange = 0;
661 		else {
662 			if (sdl->sdl_alen) {
663 				if (bcmp(lladdr, LLADDR(sdl), ifp->if_addrlen))
664 					llchange = 1;
665 				else
666 					llchange = 0;
667 			} else
668 				llchange = 1;
669 		}
670 
671 		/*
672 		 * This is VERY complex.  Look at it with care.
673 		 *
674 		 * override solicit lladdr llchange	action
675 		 *					(L: record lladdr)
676 		 *
677 		 *	0	0	n	--	(2c)
678 		 *	0	0	y	n	(2b) L
679 		 *	0	0	y	y	(1)    REACHABLE->STALE
680 		 *	0	1	n	--	(2c)   *->REACHABLE
681 		 *	0	1	y	n	(2b) L *->REACHABLE
682 		 *	0	1	y	y	(1)    REACHABLE->STALE
683 		 *	1	0	n	--	(2a)
684 		 *	1	0	y	n	(2a) L
685 		 *	1	0	y	y	(2a) L *->STALE
686 		 *	1	1	n	--	(2a)   *->REACHABLE
687 		 *	1	1	y	n	(2a) L *->REACHABLE
688 		 *	1	1	y	y	(2a) L *->REACHABLE
689 		 */
690 		if (!is_override && (lladdr && llchange)) {	   /* (1) */
691 			/*
692 			 * If state is REACHABLE, make it STALE.
693 			 * no other updates should be done.
694 			 */
695 			if (ln->ln_state == ND6_LLINFO_REACHABLE)
696 				ln->ln_state = ND6_LLINFO_STALE;
697 			goto freeit;
698 		} else if (is_override				   /* (2a) */
699 			|| (!is_override && (lladdr && !llchange)) /* (2b) */
700 			|| !lladdr) {				   /* (2c) */
701 			/*
702 			 * Update link-local address, if any.
703 			 */
704 			if (lladdr) {
705 				sdl->sdl_alen = ifp->if_addrlen;
706 				bcopy(lladdr, LLADDR(sdl), ifp->if_addrlen);
707 			}
708 
709 			/*
710 			 * If solicited, make the state REACHABLE.
711 			 * If not solicited and the link-layer address was
712 			 * changed, make it STALE.
713 			 */
714 			if (is_solicited) {
715 				ln->ln_state = ND6_LLINFO_REACHABLE;
716 				if (ln->ln_expire) {
717 					ln->ln_expire = time.tv_sec +
718 						nd_ifinfo[ifp->if_index].reachable;
719 				}
720 			} else {
721 				if (lladdr && llchange)
722 					ln->ln_state = ND6_LLINFO_STALE;
723 			}
724 		}
725 
726 		if (ln->ln_router && !is_router) {
727 			/*
728 			 * The peer dropped the router flag.
729 			 * Remove the sender from the Default Router List and
730 			 * update the Destination Cache entries.
731 			 */
732 			struct nd_defrouter *dr;
733 			struct in6_addr *in6;
734 			int s;
735 
736 			in6 = &((struct sockaddr_in6 *)rt_key(rt))->sin6_addr;
737 			s = splsoftnet();
738 			dr = defrouter_lookup(in6, rt->rt_ifp);
739 			if (dr)
740 				defrtrlist_del(dr);
741 			else if (!ip6_forwarding && ip6_accept_rtadv) {
742 				/*
743 				 * Even if the neighbor is not in the default
744 				 * router list, the neighbor may be used
745 				 * as a next hop for some destinations
746 				 * (e.g. redirect case). So we must
747 				 * call rt6_flush explicitly.
748 				 */
749 				rt6_flush(&ip6->ip6_src, rt->rt_ifp);
750 			}
751 			splx(s);
752 		}
753 		ln->ln_router = is_router;
754 	}
755 	rt->rt_flags &= ~RTF_REJECT;
756 	ln->ln_asked = 0;
757 	if (ln->ln_hold) {
758 #ifdef OLDIP6OUTPUT
759 		(*ifp->if_output)(ifp, ln->ln_hold, rt_key(rt), rt);
760 #else
761 		/*
762 		 * we assume ifp is not a p2p here, so just set the 2nd
763 		 * argument as the 1st one.
764 		 */
765 		nd6_output(ifp, ifp, ln->ln_hold,
766 			   (struct sockaddr_in6 *)rt_key(rt), rt);
767 #endif
768 		ln->ln_hold = 0;
769 	}
770 
771  freeit:
772 	m_freem(m);
773 }
774 
775 /*
776  * Neighbor advertisement output handling.
777  *
778  * Based on RFC 2461
779  *
780  * the following items are not implemented yet:
781  * - proxy advertisement delay rule (RFC2461 7.2.8, last paragraph, SHOULD)
782  * - anycast advertisement delay rule (RFC2461 7.2.7, SHOULD)
783  */
784 void
785 nd6_na_output(ifp, daddr6, taddr6, flags, tlladdr, sdl0)
786 	struct ifnet *ifp;
787 	struct in6_addr *daddr6, *taddr6;
788 	u_long flags;
789 	int tlladdr;		/* 1 if include target link-layer address */
790 	struct sockaddr *sdl0;	/* sockaddr_dl (= proxy NA) or NULL */
791 {
792 	struct mbuf *m;
793 	struct ip6_hdr *ip6;
794 	struct nd_neighbor_advert *nd_na;
795 	struct in6_ifaddr *ia = NULL;
796 	struct ip6_moptions im6o;
797 	int icmp6len;
798 	int maxlen;
799 	caddr_t mac;
800 	struct ifnet *outif = NULL;
801 
802 	/* estimate the size of message */
803 	maxlen = sizeof(*ip6) + sizeof(*nd_na);
804 	maxlen += (sizeof(struct nd_opt_hdr) + ifp->if_addrlen + 7) & ~7;
805 	if (max_linkhdr + maxlen >= MCLBYTES) {
806 #ifdef DIAGNOSTIC
807 		printf("nd6_na_output: max_linkhdr + maxlen >= MCLBYTES "
808 		    "(%d + %d > %d)\n", max_linkhdr, maxlen, MCLBYTES);
809 #endif
810 		return;
811 	}
812 
813 	MGETHDR(m, M_DONTWAIT, MT_DATA);
814 	if (m && max_linkhdr + maxlen >= MHLEN) {
815 		MCLGET(m, M_DONTWAIT);
816 		if ((m->m_flags & M_EXT) == 0) {
817 			m_free(m);
818 			m = NULL;
819 		}
820 	}
821 	if (m == NULL)
822 		return;
823 
824 	if (IN6_IS_ADDR_MULTICAST(daddr6)) {
825 		m->m_flags |= M_MCAST;
826 		im6o.im6o_multicast_ifp = ifp;
827 		im6o.im6o_multicast_hlim = 255;
828 		im6o.im6o_multicast_loop = 0;
829 	}
830 
831 	icmp6len = sizeof(*nd_na);
832 	m->m_pkthdr.len = m->m_len = sizeof(struct ip6_hdr) + icmp6len;
833 	m->m_data += max_linkhdr;	/*or MH_ALIGN() equivalent?*/
834 
835 	/* fill neighbor advertisement packet */
836 	ip6 = mtod(m, struct ip6_hdr *);
837 	ip6->ip6_flow = 0;
838 	ip6->ip6_vfc &= ~IPV6_VERSION_MASK;
839 	ip6->ip6_vfc |= IPV6_VERSION;
840 	ip6->ip6_nxt = IPPROTO_ICMPV6;
841 	ip6->ip6_hlim = 255;
842 	if (IN6_IS_ADDR_UNSPECIFIED(daddr6)) {
843 		/* reply to DAD */
844 		ip6->ip6_dst.s6_addr16[0] = IPV6_ADDR_INT16_MLL;
845 		ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
846 		ip6->ip6_dst.s6_addr32[1] = 0;
847 		ip6->ip6_dst.s6_addr32[2] = 0;
848 		ip6->ip6_dst.s6_addr32[3] = IPV6_ADDR_INT32_ONE;
849 		flags &= ~ND_NA_FLAG_SOLICITED;
850 	} else
851 		ip6->ip6_dst = *daddr6;
852 
853 	/*
854 	 * Select a source whose scope is the same as that of the dest.
855 	 */
856 	ia = in6_ifawithifp(ifp, &ip6->ip6_dst);
857 	if (ia == NULL) {
858 		m_freem(m);
859 		return;
860 	}
861 	ip6->ip6_src = ia->ia_addr.sin6_addr;
862 	nd_na = (struct nd_neighbor_advert *)(ip6 + 1);
863 	nd_na->nd_na_type = ND_NEIGHBOR_ADVERT;
864 	nd_na->nd_na_code = 0;
865 	nd_na->nd_na_target = *taddr6;
866 	if (IN6_IS_SCOPE_LINKLOCAL(&nd_na->nd_na_target))
867 		nd_na->nd_na_target.s6_addr16[1] = 0;
868 
869 	/*
870 	 * "tlladdr" indicates NS's condition for adding tlladdr or not.
871 	 * see nd6_ns_input() for details.
872 	 * Basically, if NS packet is sent to unicast/anycast addr,
873 	 * target lladdr option SHOULD NOT be included.
874 	 */
875 	if (tlladdr) {
876 		mac = NULL;
877 		/*
878 		 * sdl0 != NULL indicates proxy NA.  If we do proxy, use
879 		 * lladdr in sdl0.  If we are not proxying (sending NA for
880 		 * my address) use lladdr configured for the interface.
881 		 */
882 		if (sdl0 == NULL)
883 			mac = nd6_ifptomac(ifp);
884 		else if (sdl0->sa_family == AF_LINK) {
885 			struct sockaddr_dl *sdl;
886 			sdl = (struct sockaddr_dl *)sdl0;
887 			if (sdl->sdl_alen == ifp->if_addrlen)
888 				mac = LLADDR(sdl);
889 		}
890 	}
891 	if (tlladdr && mac) {
892 		int optlen = sizeof(struct nd_opt_hdr) + ifp->if_addrlen;
893 		struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)(nd_na + 1);
894 
895 		/* roundup to 8 bytes alignment! */
896 		optlen = (optlen + 7) & ~7;
897 
898 		m->m_pkthdr.len += optlen;
899 		m->m_len += optlen;
900 		icmp6len += optlen;
901 		bzero((caddr_t)nd_opt, optlen);
902 		nd_opt->nd_opt_type = ND_OPT_TARGET_LINKADDR;
903 		nd_opt->nd_opt_len = optlen >> 3;
904 		bcopy(mac, (caddr_t)(nd_opt + 1), ifp->if_addrlen);
905 	} else
906 		flags &= ~ND_NA_FLAG_OVERRIDE;
907 
908 	ip6->ip6_plen = htons((u_short)icmp6len);
909 	nd_na->nd_na_flags_reserved = flags;
910 	nd_na->nd_na_cksum = 0;
911 	nd_na->nd_na_cksum =
912 		in6_cksum(m, IPPROTO_ICMPV6, sizeof(struct ip6_hdr), icmp6len);
913 
914 #ifdef IPSEC
915 	/* Don't lookup socket */
916 	ipsec_setsocket(m, NULL);
917 #endif
918 	ip6_output(m, NULL, NULL, 0, &im6o, &outif);
919 	if (outif) {
920 		icmp6_ifstat_inc(outif, ifs6_out_msg);
921 		icmp6_ifstat_inc(outif, ifs6_out_neighboradvert);
922 	}
923 	icmp6stat.icp6s_outhist[ND_NEIGHBOR_ADVERT]++;
924 }
925 
926 caddr_t
927 nd6_ifptomac(ifp)
928 	struct ifnet *ifp;
929 {
930 	switch (ifp->if_type) {
931 	case IFT_ARCNET:
932 	case IFT_ETHER:
933 	case IFT_FDDI:
934 	case IFT_IEEE1394:
935 		return LLADDR(ifp->if_sadl);
936 		break;
937 	default:
938 		return NULL;
939 	}
940 }
941 
942 TAILQ_HEAD(dadq_head, dadq);
943 struct dadq {
944 	TAILQ_ENTRY(dadq) dad_list;
945 	struct ifaddr *dad_ifa;
946 	int dad_count;		/* max NS to send */
947 	int dad_ns_tcount;	/* # of trials to send NS */
948 	int dad_ns_ocount;	/* NS sent so far */
949 	int dad_ns_icount;
950 	int dad_na_icount;
951 	struct callout dad_timer_ch;
952 };
953 
954 static struct dadq_head dadq;
955 
956 static struct dadq *
957 nd6_dad_find(ifa)
958 	struct ifaddr *ifa;
959 {
960 	struct dadq *dp;
961 
962 	for (dp = dadq.tqh_first; dp; dp = dp->dad_list.tqe_next) {
963 		if (dp->dad_ifa == ifa)
964 			return dp;
965 	}
966 	return NULL;
967 }
968 
969 /*
970  * Start Duplicated Address Detection (DAD) for specified interface address.
971  */
972 void
973 nd6_dad_start(ifa, tick)
974 	struct ifaddr *ifa;
975 	int *tick;	/* minimum delay ticks for IFF_UP event */
976 {
977 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
978 	struct dadq *dp;
979 	static int dad_init = 0;
980 
981 	if (!dad_init) {
982 		TAILQ_INIT(&dadq);
983 		dad_init++;
984 	}
985 
986 	/*
987 	 * If we don't need DAD, don't do it.
988 	 * There are several cases:
989 	 * - DAD is disabled (ip6_dad_count == 0)
990 	 * - the interface address is anycast
991 	 */
992 	if (!(ia->ia6_flags & IN6_IFF_TENTATIVE)) {
993 		log(LOG_DEBUG,
994 			"nd6_dad_start: called with non-tentative address "
995 			"%s(%s)\n",
996 			ip6_sprintf(&ia->ia_addr.sin6_addr),
997 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
998 		return;
999 	}
1000 	if (ia->ia6_flags & IN6_IFF_ANYCAST) {
1001 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1002 		return;
1003 	}
1004 	if (!ip6_dad_count) {
1005 		ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1006 		return;
1007 	}
1008 	if (!ifa->ifa_ifp)
1009 		panic("nd6_dad_start: ifa->ifa_ifp == NULL");
1010 	if (!(ifa->ifa_ifp->if_flags & IFF_UP))
1011 		return;
1012 	if (nd6_dad_find(ifa) != NULL) {
1013 		/* DAD already in progress */
1014 		return;
1015 	}
1016 
1017 	dp = malloc(sizeof(*dp), M_IP6NDP, M_NOWAIT);
1018 	if (dp == NULL) {
1019 		log(LOG_ERR, "nd6_dad_start: memory allocation failed for "
1020 			"%s(%s)\n",
1021 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1022 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1023 		return;
1024 	}
1025 	bzero(dp, sizeof(*dp));
1026 	callout_init(&dp->dad_timer_ch);
1027 	TAILQ_INSERT_TAIL(&dadq, (struct dadq *)dp, dad_list);
1028 
1029 #ifdef ND6_DEBUG
1030 	log(LOG_DEBUG, "%s: starting DAD for %s\n", if_name(ifa->ifa_ifp),
1031 	    ip6_sprintf(&ia->ia_addr.sin6_addr));
1032 #endif
1033 
1034 	/*
1035 	 * Send NS packet for DAD, ip6_dad_count times.
1036 	 * Note that we must delay the first transmission, if this is the
1037 	 * first packet to be sent from the interface after interface
1038 	 * (re)initialization.
1039 	 */
1040 	dp->dad_ifa = ifa;
1041 	IFAREF(ifa);		/* just for safety */
1042 	dp->dad_count = ip6_dad_count;
1043 	dp->dad_ns_icount = dp->dad_na_icount = 0;
1044 	dp->dad_ns_ocount = dp->dad_ns_tcount = 0;
1045 	if (!tick) {
1046 		nd6_dad_ns_output(dp, ifa);
1047 		callout_reset(&dp->dad_timer_ch,
1048 		    nd_ifinfo[ifa->ifa_ifp->if_index].retrans * hz / 1000,
1049 		    (void (*) __P((void *)))nd6_dad_timer, ifa);
1050 	} else {
1051 		int ntick;
1052 
1053 		if (*tick == 0)
1054 			ntick = random() % (MAX_RTR_SOLICITATION_DELAY * hz);
1055 		else
1056 			ntick = *tick + random() % (hz / 2);
1057 		*tick = ntick;
1058 		callout_reset(&dp->dad_timer_ch, ntick,
1059 		    (void (*) __P((void *)))nd6_dad_timer, ifa);
1060 	}
1061 }
1062 
1063 static void
1064 nd6_dad_timer(ifa)
1065 	struct ifaddr *ifa;
1066 {
1067 	int s;
1068 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1069 	struct dadq *dp;
1070 
1071 	s = splsoftnet();	/*XXX*/
1072 
1073 	/* Sanity check */
1074 	if (ia == NULL) {
1075 		log(LOG_ERR, "nd6_dad_timer: called with null parameter\n");
1076 		goto done;
1077 	}
1078 	dp = nd6_dad_find(ifa);
1079 	if (dp == NULL) {
1080 		log(LOG_ERR, "nd6_dad_timer: DAD structure not found\n");
1081 		goto done;
1082 	}
1083 	if (ia->ia6_flags & IN6_IFF_DUPLICATED) {
1084 		log(LOG_ERR, "nd6_dad_timer: called with duplicated address "
1085 			"%s(%s)\n",
1086 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1087 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1088 		goto done;
1089 	}
1090 	if ((ia->ia6_flags & IN6_IFF_TENTATIVE) == 0) {
1091 		log(LOG_ERR, "nd6_dad_timer: called with non-tentative address "
1092 			"%s(%s)\n",
1093 			ip6_sprintf(&ia->ia_addr.sin6_addr),
1094 			ifa->ifa_ifp ? if_name(ifa->ifa_ifp) : "???");
1095 		goto done;
1096 	}
1097 
1098 	/* timeouted with IFF_{RUNNING,UP} check */
1099 	if (dp->dad_ns_tcount > dad_maxtry) {
1100 		log(LOG_ERR, "%s: could not run DAD, driver problem?\n",
1101 		    if_name(ifa->ifa_ifp));
1102 
1103 		TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1104 		free(dp, M_IP6NDP);
1105 		dp = NULL;
1106 		IFAFREE(ifa);
1107 		goto done;
1108 	}
1109 
1110 	/* Need more checks? */
1111 	if (dp->dad_ns_ocount < dp->dad_count) {
1112 		/*
1113 		 * We have more NS to go.  Send NS packet for DAD.
1114 		 */
1115 		nd6_dad_ns_output(dp, ifa);
1116 		callout_reset(&dp->dad_timer_ch,
1117 		    nd_ifinfo[ifa->ifa_ifp->if_index].retrans * hz / 1000,
1118 		    (void (*) __P((void *)))nd6_dad_timer, ifa);
1119 	} else {
1120 		/*
1121 		 * We have transmitted sufficient number of DAD packets.
1122 		 * See what we've got.
1123 		 */
1124 		int duplicate;
1125 
1126 		duplicate = 0;
1127 
1128 		if (dp->dad_na_icount) {
1129 			/*
1130 			 * the check is in nd6_dad_na_input(),
1131 			 * but just in case
1132 			 */
1133 			duplicate++;
1134 		}
1135 
1136 		if (dp->dad_ns_icount) {
1137 #if 0 /*heuristics*/
1138 			/*
1139 			 * if
1140 			 * - we have sent many(?) DAD NS, and
1141 			 * - the number of NS we sent equals to the
1142 			 *   number of NS we've got, and
1143 			 * - we've got no NA
1144 			 * we may have a faulty network card/driver which
1145 			 * loops back multicasts to myself.
1146 			 */
1147 			if (3 < dp->dad_count
1148 			 && dp->dad_ns_icount == dp->dad_count
1149 			 && dp->dad_na_icount == 0) {
1150 				log(LOG_INFO, "DAD questionable for %s(%s): "
1151 					"network card loops back multicast?\n",
1152 					ip6_sprintf(&ia->ia_addr.sin6_addr),
1153 					if_name(ifa->ifa_ifp));
1154 				/* XXX consider it a duplicate or not? */
1155 				/* duplicate++; */
1156 			} else {
1157 				/* We've seen NS, means DAD has failed. */
1158 				duplicate++;
1159 			}
1160 #else
1161 			/* We've seen NS, means DAD has failed. */
1162 			duplicate++;
1163 #endif
1164 		}
1165 
1166 		if (duplicate) {
1167 			/* (*dp) will be freed in nd6_dad_duplicated() */
1168 			dp = NULL;
1169 			nd6_dad_duplicated(ifa);
1170 		} else {
1171 			/*
1172 			 * We are done with DAD.  No NA came, no NS came.
1173 			 * duplicated address found.
1174 			 */
1175 			ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1176 
1177 #ifdef ND6_DEBUG
1178 			log(LOG_DEBUG,
1179 			    "%s: DAD complete for %s - no duplicates found\n",
1180 			    if_name(ifa->ifa_ifp),
1181 			    ip6_sprintf(&ia->ia_addr.sin6_addr));
1182 #endif
1183 
1184 			TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1185 			free(dp, M_IP6NDP);
1186 			dp = NULL;
1187 			IFAFREE(ifa);
1188 		}
1189 	}
1190 
1191 done:
1192 	splx(s);
1193 }
1194 
1195 void
1196 nd6_dad_duplicated(ifa)
1197 	struct ifaddr *ifa;
1198 {
1199 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1200 	struct dadq *dp;
1201 
1202 	dp = nd6_dad_find(ifa);
1203 	if (dp == NULL) {
1204 		log(LOG_ERR, "nd6_dad_duplicated: DAD structure not found\n");
1205 		return;
1206 	}
1207 
1208 	log(LOG_ERR, "%s: DAD detected duplicate IPv6 address %s: %d NS, "
1209 	    "%d NA\n", if_name(ifa->ifa_ifp),
1210 	    ip6_sprintf(&ia->ia_addr.sin6_addr),
1211 	    dp->dad_ns_icount, dp->dad_na_icount);
1212 
1213 	ia->ia6_flags &= ~IN6_IFF_TENTATIVE;
1214 	ia->ia6_flags |= IN6_IFF_DUPLICATED;
1215 
1216 	/* We are done with DAD, with duplicated address found. (failure) */
1217 	callout_stop(&dp->dad_timer_ch);
1218 
1219 	log(LOG_ERR, "%s: DAD complete for %s - duplicate found\n",
1220 	    if_name(ifa->ifa_ifp), ip6_sprintf(&ia->ia_addr.sin6_addr));
1221 	log(LOG_ERR, "%s: manual intervention required\n",
1222 	    if_name(ifa->ifa_ifp));
1223 
1224 	TAILQ_REMOVE(&dadq, (struct dadq *)dp, dad_list);
1225 	free(dp, M_IP6NDP);
1226 	dp = NULL;
1227 	IFAFREE(ifa);
1228 }
1229 
1230 static void
1231 nd6_dad_ns_output(dp, ifa)
1232 	struct dadq *dp;
1233 	struct ifaddr *ifa;
1234 {
1235 	struct in6_ifaddr *ia = (struct in6_ifaddr *)ifa;
1236 	struct ifnet *ifp = ifa->ifa_ifp;
1237 
1238 	dp->dad_ns_tcount++;
1239 	if ((ifp->if_flags & IFF_UP) == 0) {
1240 #if 0
1241 		printf("%s: interface down?\n", if_name(ifp));
1242 #endif
1243 		return;
1244 	}
1245 	if ((ifp->if_flags & IFF_RUNNING) == 0) {
1246 #if 0
1247 		printf("%s: interface not running?\n", if_name(ifp));
1248 #endif
1249 		return;
1250 	}
1251 
1252 	dp->dad_ns_ocount++;
1253 	nd6_ns_output(ifp, NULL, &ia->ia_addr.sin6_addr, NULL, 1);
1254 }
1255 
1256 static void
1257 nd6_dad_ns_input(ifa)
1258 	struct ifaddr *ifa;
1259 {
1260 	struct in6_ifaddr *ia;
1261 	struct ifnet *ifp;
1262 	struct in6_addr *taddr6;
1263 	struct dadq *dp;
1264 	int duplicate;
1265 
1266 	if (!ifa)
1267 		panic("ifa == NULL in nd6_dad_ns_input");
1268 
1269 	ia = (struct in6_ifaddr *)ifa;
1270 	ifp = ifa->ifa_ifp;
1271 	taddr6 = &ia->ia_addr.sin6_addr;
1272 	duplicate = 0;
1273 	dp = nd6_dad_find(ifa);
1274 
1275 	/*
1276 	 * If it is from myself, ignore this.
1277 	 */
1278 	if (ifp && (ifp->if_flags & IFF_LOOPBACK))
1279 		return;
1280 
1281 	/* Quickhack - completely ignore DAD NS packets */
1282 	if (dad_ignore_ns) {
1283 		log(LOG_INFO, "nd6_dad_ns_input: ignoring DAD NS packet for "
1284 		    "address %s(%s)\n", ip6_sprintf(taddr6),
1285 		    if_name(ifa->ifa_ifp));
1286 		return;
1287 	}
1288 
1289 	/*
1290 	 * if I'm yet to start DAD, someone else started using this address
1291 	 * first.  I have a duplicate and you win.
1292 	 */
1293 	if (!dp || dp->dad_ns_ocount == 0)
1294 		duplicate++;
1295 
1296 	/* XXX more checks for loopback situation - see nd6_dad_timer too */
1297 
1298 	if (duplicate) {
1299 		dp = NULL;	/* will be freed in nd6_dad_duplicated() */
1300 		nd6_dad_duplicated(ifa);
1301 	} else {
1302 		/*
1303 		 * not sure if I got a duplicate.
1304 		 * increment ns count and see what happens.
1305 		 */
1306 		if (dp)
1307 			dp->dad_ns_icount++;
1308 	}
1309 }
1310 
1311 static void
1312 nd6_dad_na_input(ifa)
1313 	struct ifaddr *ifa;
1314 {
1315 	struct dadq *dp;
1316 
1317 	if (!ifa)
1318 		panic("ifa == NULL in nd6_dad_na_input");
1319 
1320 	dp = nd6_dad_find(ifa);
1321 	if (dp)
1322 		dp->dad_na_icount++;
1323 
1324 	/* remove the address. */
1325 	nd6_dad_duplicated(ifa);
1326 }
1327